Détails:Flight 410 departed Chicago, at 13:52 on an instrument flight plan with destination Norfolk and with stops scheduled at Cleveland, Pittsburgh and Washington. The flight departed Pittsburgh at 17:24 proceeded to Washington at 7,000 feet. At 18:03 the plane started its descent into Washington. While descending, the plane struck a ridge named Lookout Rock in the Blue Ridge Mountains at an elevation of approximately 1,425 feet

Probable Cause:

PROBABLE CAUSE: "The Board finds that the probable cause of this accident was the action of the pilot in descending below the minimum en route altitude under conditions of weather which prevented adequate visual reference to the ground. A contributing cause was the faulty clearance given by Airway Traffic Control, tacitly approved by the company dispatcher, and accepted by Flight 410."